The blood collection vessel additive is used to separate serum and blood clots. The serum separating gel is a mixture of high molecular polymers, which is polymerized from a variety of monomers with different relative molecular weights. Due to its large relative molecular weight, it presents a uniform gel shape. Serum separation gel is a substance used to separate serum from coagulated whole blood or plasma from cells. It forms an isolation layer between the cellular components of blood and serum, effectively preventing material exchange between blood cells and serum, and ensuring the stability of serum components for a certain period of time. Firstly, the ability of serum separation gel to separate serum and blood clots is due to its thixotropy, which means that under the action of centrifugal force, the network structure of serum separation gel is destroyed and becomes a low viscosity fluid. After the centrifugal force disappears, it forms a network structure again and returns to a fluid with high viscosity. This property is called thixotropy. Therefore, under the action of thrombin, the blood will form serum and blood clots. Under the action of centrifugal force, the separation gel changes from a colloid to a liquid with fluidity and moves upwards, preventing the exchange of substances between serum and blood clots. Then, the serum separation gel can separate serum and blood clots because the specific gravity of the serum separation gel is between 1.045 and 1.065, the specific gravity of the blood clot is around 1.092g/ml, and the specific gravity of the serum is around 1.025 to 1.030g/ml. Therefore, the specific gravity of the separation gel is in the middle, so the separation gel can effectively isolate in a completely solidified state. Rapid separation of serum/blood clots is achieved through centrifugation to obtain high-quality samples that can be transported and transferred.